<template>
  <div id="app">
    <router-view></router-view>
  </div>
</template>

<script>

export default {
  name: 'app',
  components: {
    
  },
  created() {
     // 在页面加载时读取sessionStorage里的状态信息
     if (sessionStorage.getItem('store')) {
       this.$store.replaceState(
         Object.assign(
           {},
           this.$store.state,
           JSON.parse(sessionStorage.getItem('store'))
         )
       )
     }
     // 在页面刷新时将vuex里的信息保存到sessionStorage里,beforeunload事件在页面刷新时先触发
     window.addEventListener('beforeunload', () => {
       sessionStorage.setItem('store', JSON.stringify(this.$store.state))
     })
   },

}
</script>

<style>
  html, body {
    margin:0;
    padding:0;
  }
#app {
  height: 100vh;
  
}
</style>
